This invention relates to a manually-operated device for inflating a vehicle tire. For safe driving, it is very important to keep the car tires at a suitable pressure determined according to local climate, car model, and regular driving speed. If the car tire pressure is excessively low, while driving under high speed, the friction resistance will be increased, and therefore, steering control will be more difficult. Also, the car tires will tend to wear prematurely. When a tire (high-speed tire) is pierced by a nail to exhaust, the tire should be replaced by a spare tire. If no suitable spare tire is available, the driver will have to inflate the tire by oneself or contact a maintenance shop for tire repair or replacement.
A car maintenance shop will have a pressure gauge for checking the tire pressure. However, the ordinary car driver will not have a pressure gauge to accurately control tire pressure while using a tire inflator to inflate the tires. In consequence, car tire pressure may be over or below the normal optimum range when the car owner inflates the tire.